Tread rubber composition with majority renewable content

ABSTRACT

A tire component formed from a rubber composition comprises a majority weight percent of renewable materials. The rubber composition comprises, based on 100 parts per weight (phr) of elastomer: a blend of at least two rubber elastomers selected from a group consisting of: from about 15 phr to about 50 phr polybutadiene; up to about 20 phr of styrenebutadiene copolymer; up to about 90 phr of natural rubber; a bio-derived resin material; a vegetable triglyceride oil; and a bio-derived filler comprising silica and carbon black filler. The carbon black filler is at least partially derived from a bio-based feedstock prior to its addition to the rubber composition. The resin and the silica are also derived from renewable materials. In some embodiments, the contemplated polybutadiene may be from mass balanced feedstocks.

FIELD OF THE INVENTION

This application claims priority to U.S. Provisional Serial No.63/265,703 (the “’703 provisional”), filed Dec. 20, 2021. Thisapplication is also a continuation-in-part of U.S. Pat. Application Ser.No. 18/046,190, filed Oct. 13, 2022, which also claims the prioritybenefit of the ‘703 provisional. These applications are incorporatedherein by reference in their entireties.

FIELD OF THE INVENTION

The present exemplary embodiments relate to a tire rubber compositioncontaining a majority weight percent of renewable content. It findsparticular application in conjunction with tread components and will bedescribed with particular reference thereto. However, it is to beappreciated that the present exemplary embodiments are also amenable toother like applications.

BACKGROUND OF THE INVENTION

To improve sustainability in the tire industry, there is an ongoingeffort to develop rubber tire compositions from renewable sources.However, sustainable compositions must behave in predicted ways for atire to perform to its intended purpose. Therefore, a sustainable rubbercomposition is desired from which there is little to no compromise inrubber performance.

In rubber tire compounds, each material and additive are combined withelastomers to impart specific properties in the resulting tire.Presently, several materials-resin and carbon black being two amongthem—are derived from a fossil (also referred to herein as“hydrocarbon”) fuel source (i.e., petroleum, coal, or natural gas).Emissions from the manufacture of these petroleum-derived materialsinclude organics, sulfur compounds, carbon monoxide (CO), and othercontaminants. To lessen the environmental impact of such emissions,there is a desire to reduce, or altogether exclude, from rubbercompounds the materials that originate from fossil fuel sources.However, previous technologies have made it difficult for one, let alonea combination of, bio-derived alternative materials to replicate theperformance of conventional materials in tire compounds.

To meet the challenge of providing a tire rubber composition fromsustainable, bio-renewable, environmentally friendly, and non-fossilfuel sources, it is desired to evaluate a rubber composition formed froma combination of materials including resin derived from a renewableresource.

SUMMARY OF THE INVENTION

One embodiment of the disclosure relates to a tire component formed froma rubber composition comprising a majority weight percent of renewablematerials. The rubber composition comprises, based on 100 parts perweight (phr) of elastomer:

-   a blend of at least two rubber elastomers selected from a group    consisting of:    -   from about 15 phr to about 50 phr polybutadiene;    -   up to about 20 phr of styrene-butadiene copolymer; and    -   up to about 90 phr of natural rubber;-   a bio-derived resin material;-   a vegetable triglyceride oil; and-   a bio-derived filler comprising silica and carbon black filler. In    the contemplated embodiment, the carbon black filler is at least    partially derived from a bio-based feedstock prior to its addition    to the rubber composition. The resin and the silica are also derived    from renewable materials. In some embodiments, the contemplated    polybutadiene may be from mass balanced feedstocks.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by way of example and with reference tothe accompanying drawing in which:

FIG. 1 is a chart mapping out rolling resistance, snow, and wetperformance indicators between a conventional compound and workingsamples according to embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure relates to a rubber composition containing amajority weight percent of renewable content. The disclosure furtherrelates to a rubber tire having a tire component comprising thecompound.

As used herein, the terms “compounded rubber”, “rubber compound” and“compound” refer to rubber compositions containing elastomers which havebeen compounded, or blended, with appropriate rubber compoundingingredients. The terms “rubber” and “elastomer” and “polymer” may beused interchangeably unless otherwise indicated. It is believed thatsuch terms are well known to those having skill in the art.

As used herein, except where context requires otherwise, the term“comprise” and variations of the term, such as “comprising”, “comprises”and “comprised”, are not intended to exclude further additives,components, integers, or steps. As used herein, the words “from about”means approximately and can includes values ±1 beyond the ones listedherein.

As used herein, the term “sustainable” encompasses raw materials madefrom processes or technologies that reduce carbon emissions and/orresource consumption, and/or recycled, renewable, bio-based, bio-derivedand mass balanced raw materials.

As used herein, the term “bio-based” or “bio-derived” refers to acircular material or a material derived from a renewable or sustainableresource or natural source, and may even include an industrial sourcewhen, for example, a byproduct or waste product is being captured andreused to reduce or eliminate emissions and/or landfill waste that isharmful to the environment. One non-limiting example is thesequestration of carbon oxides for use as feedstock.

It partially, and more preferably fully, excludes radiocarbon and fossilcarbon materials derived from petroleum, coal, or a natural gas source.Examples of resources from which the bio-based material can be derivedinclude, but are not limited to, fresh (or from the fermentation ofbiomass material, such as corn, vegetable oils, etc.

As used herein “mass balanced” means that at least a portion of thefeedstock used to synthesize a material, such as a rubber polymer, resinor filler, is circular or bio-based. In practice, the process, such asthe tire pyrolysis process (TPO), may be certified as mass-balancerenewable. In the contemplated embodiment, at least 0.1%, and morepreferably at least 1%, and most preferably at least 5%, of thefeedstock to produce the polymer is circular or bio-based. In otherwords, a contemplated polymer or filler is produced from a mass balanceof bio-based feedstock and traditional feedstock. One non-limitingexample of a bio-based feedstock includes tall oil but may also includebiomass, byproduct and waste products discussed supra. The term“mass-balanced” may also refer to carbon black and other byproductsobtained from the pyrolysis of scrap tires. A mass-balanced material istypically certified to the International Sustainability & CarbonCertification (ISCC) standard.

A key aspect of the disclosure is the percent weight content ofrenewable content achieved using a combination of various renewablematerials. A further aspect of the disclosed rubber composition is thatthe performance of a cured rubber composition with a majority weightpercent of renewable content matches or improves on the tread (wet,wear, and rolling resistance) performance of conventional rubbercompositions made from petroleum-derived materials.

Rubber Polymer(s)

The disclosed rubber composition comprises a blend of at least tworubber, and more particularly conjugated diene-based, elastomers. Inpractice, various conjugated diene-based elastomers may be used for therubber composition such as, for example, polymers and copolymers of atleast one of isoprene and 1,3-butadiene and of styrene copolymerizedwith at least one of isoprene and 1,3-butadiene. Representative of suchconjugated diene-based elastomers are, for example, comprised of atleast one of cis 1,4-polyisoprene (natural and synthetic), cis1,4-polybutadiene, styrene/butadiene copolymers, medium vinylpolybutadiene having a vinyl 1,2-content in a range of about 15 to about90 percent, isoprene/butadiene copolymers, andstyrene/isoprene/butadiene terpolymers.

In practice, the preferred rubber or elastomers are polyisoprene(natural or synthetic), polybutadiene and SBR. In further embodiment,the rubber elastomers are polyisoprene and polybutadiene. In oneembodiment, the polybutadiene is present in a majority amount. In apreferred embodiment, the polyisoprene is present in a majority amount.The synthetic rubber elastomers are preferably ISCC certified polymers.Examples of mass balanced elastomers can include SBR and polybutadienein which circular or renewable feedstock are employed to synthesize thepolymers. Non-limiting examples of polymers that can be employed in thedisclosed rubber composition can include any ISCC polymer, such as ISCCpolybutadienes available as EUROPRENE® Neocis BR 40 by Versalis and BUD1224 by The Goodyear Tire & Rubber Company. In practice, a combinationof natural and mass balanced polymers may be used.

In one embodiment, the rubber composition comprises from about 1 toabout 90 phr polybutadiene and, more preferably from about 10 phr toabout 60 phr polybutadiene. In one embodiment, the rubber compositioncomprises up to 20% weight percent of polybutadiene.

In practice, it is envisioned that the cis 1,4-polybutadiene elastomermay be a neodymium catalyst prepared cis 1,4-polybutadiene rubber whichmay be prepared, for example, by polymerization of 1,3-polybutadienemonomer in an organic solvent solution in the presence of a catalystsystem comprised of neodymium compound. However, such 1,4-polybutadienecan be prepared by organic solution nickel catalysis of cis1,3-budadiene rubber instead.

Representative of such neodymium catalyst prepared cis 1,4-polybutdieneis, for example, and not intended to be limiting, BUD 1223™ from TheGoodyear Tire & Rubber Company and CB25™ from Lanxess.

The cis 1,4-polyisoprene and cis 1,4-polyisoprene natural rubber arewell known to those having skill in the rubber art. In practice, asecond rubber polymer can include a polyisoprene. In one embodiment, thepolyisoprene can be present in a minority amount. In another embodiment,the polyisoprene can be present in a majority amount. In practice, thepreferred rubber or elastomers include polyisoprene (natural orsynthetic) in some amount. In one embodiment, the rubber compositioncomprises from about 10 phr to about 100 phr of polyisoprene, preferablyin the form of natural rubber. In one embodiment, the rubber compositioncomprises at least about 50 phr and more preferably at least about 75phr of polyisoprene, preferably in the form of natural rubber.

In one contemplated embodiment, at least one rubber polymer can furtherinclude a styrene-butadiene rubber. Styrene/butadiene copolymers includethose prepared by aqueous emulsion polymerization (ESBR) and organicsolvent solution polymerization (SSBR). In one embodiment, a solutionpolymerization prepared SBR (SSBR) is also contemplated, which typicallyhas a bound styrene content in a range of about 9 to about 36 percent.However, embodiments are contemplated in which the SSBR has a boundstyrene content of greater than 30 percent, such as 34%.

The rubber composition can comprise up to about 35 phr of thestyrene-butadiene rubber. In one embodiment, the rubber compositioncomprises ESBR and SSBR. In one embodiment, the rubber compositioncomprises SSBR and excludes ESBR. For embodiments in which the blend ofrubber polymers comprises SSBR, the SSBR may be present in an amount offrom about 5 phr to about 30 phr and, more preferably, from about 10 toabout 25 phr. In certain embodiments, the rubber composition comprisesup to about 5% weight percent of SSBR.

The SSBR can be conveniently prepared, for example, by organo lithiumcatalyzation in the presence of an organic hydrocarbon solvent. In oneembodiment, the SSBR is not functionalized. In one embodiment, at leastone rubber polymer, such as the SSBR, can be functionalized.

Representative of functionalized elastomers are, for example,styrene/butadiene elastomers containing one or more functional groupscomprised of

-   (A) amine functional group reactive with hydroxyl groups on    precipitated silica,-   (B) siloxy functional group, including end chain siloxy groups,    reactive with hydroxyl groups on precipitated silica,-   (C) combination of amine and siloxy functional groups reactive with    hydroxyl groups on said precipitated silica,-   (D) combination of thiol and siloxy (e.g. ethoxysilane) functional    groups reactive with hydroxyl groups on the precipitated silica,-   (E) combination of imine and siloxy functional groups reactive with    hydroxyl groups on the precipitated silica,-   (F) hydroxyl functional groups reactive with the precipitated    silica.

For the functionalized elastomers, representatives of aminefunctionalized SBR elastomers are, for example, in-chain functionalizedSBR elastomers mentioned in U.S. Pat. No. 6,936,669.

Representative of a combination of amino-siloxy functionalized SBRelastomers with one or more amino-siloxy groups connected to theelastomer is, for example, HPR355™ from JSR and amino-siloxyfunctionalized SBR elastomers mentioned in U.S. Pat. No. 7,981,966.

Representative styrene/butadiene elastomers end functionalized with asilane-sulfide group are, for example, mentioned in U.S. Pat. Nos.8,217,103 and 8,569,409.

It is further contemplated that, in certain embodiments, the rubberelastomer may be a butyl type rubber, particularly copolymers ofisobutylene with a minor content of diene hydrocarbon(s), such as, forexample, isoprene and halogenated butyl rubber.

It is further contemplated that, in certain embodiments, the elastomermay comprise a halobutyl rubber comprising a blend consisting ofclorobutyl rubber, bromobutyl rubber and mixtures thereof.

Tin coupled elastomers may also be used, such as, for example, tincoupled organic solution polymerization prepared styrene/butadieneco-polymers, isoprene/butadiene copolymers, styrene/isoprene copolymers,polybutadiene and styrene/isoprene/butadiene terpolymers including theaforesaid functionalized styrene/butadiene elastomers.

Oil

By desiring the rubber composition to contain fewer to no materialsderived from petroleum, it is meant that the rubber composition willcontain minimal, if any, petroleum-based processing oil. For example, itis desired that the rubber composition be limited to from zero to about5 phr of petroleum-based processing oil and, more preferably, less thanabout 2 phr of rubber petroleum-based processing oil.

In one embodiment, the rubber composition may comprise up to about 20phr of rubber processing oil. In another embodiment, the rubbercomposition may comprise no less than about 1 phr of rubber processingoil. In practice, the composition may comprise from about 1 to about 20phr of rubber processing oil and, more preferably, from about 15 toabout 20 phr of rubber processing oil. Processing oil may be included inthe rubber composition as extending oil typically used to extendelastomers. Processing oil may also be included in the rubbercomposition by addition of the oil directly during rubber compounding.The processing oil used in the rubber composition may include bothextending oil present in the elastomers and process oil added duringcompounding. Suitable process oils include various oils as are known inthe art, including aromatic, paraffinic, naphthenic, vegetabletriglyceride oils, and low PCA oils, such as MES, TDAE, SRAE and heavynaphthenic oils. Suitable low PCA oils include those having a polycyclicaromatic content of less than 3 percent by weight as determined by theIP346 method. Procedures for the IP346 method may be found in StandardMethods for Analyis & Testing of Petroleum and Related Products andBritish Standard 2000 Parts, 2003, 62^(nd) edition, published by theInstitute of Petroleum, United Kingdom.

A suitable vegetable triglyceride oil is comprised of a combination ofsaturated and unsaturated esters where the unsaturated esters arecomprised of a combination of at least one of oleic acid ester,linoleate acid ester and linoleate acid ester. The saturated esters maybe comprised of, for example, and not intended to be limiting, at leastone of stearic acid ester and palmitic acid ester.

In one embodiment, the vegetable triglyceride oil is comprised of atleast one of soybean oil, sunflower oil, rapeseed oil, and canola oil,which are in the form of esters containing a certain degree ofunsaturation. Other suitable examples of vegetable triglyceride oilinclude corn, coconut, cottonseed, olive, palm, peanut, and saffloweroils. In practice, the oil includes at least one of soybean oil andsunflower oil.

In the case of soybean oil, for example, the above represented percentdistribution, or combination, of the fatty acids for the glyceroltri-esters, namely the triglycerides, is represented as being an averagevalue and may vary somewhat depending primarily on the type, or sourceof the soybean crop, and may also depend on the growing conditions of aparticular soybean crop from which the soybean oil was obtained. Thereare also significant amounts of other saturated fatty acids typicallypresent, though these usually do not exceed 20 percent of the soybeanoil.

The contemplated embodiment comprises between about 1% and 10% weightpercent of a bio-derived rubber processing oil in the composition. Inone embodiment, the rubber processing oil material makes up from about3% weight percent and 8% weight percent of the composition.

Resin

A critical aspect of the present disclosure is the use of a bio-derivedresin material, partially, but preferably fully, in place of a petroleumresin. Conventional resins are derived from petroleum. These type ofresins include any hydrocarbon chemistry type resin (AMS,coumarone-indene, C5, C9, C5/C9, DCPD, DCPD/C9, others) & anymodification thereof (phenol, C9, hydrogenation, recycled monomers,others). While these type of resins are contemplated for use in oneembodiment of the invention, the preferred embodiment instead employs arenewable biobased chemistry type resin & modification and mixturethereof. Representative resins can also include coumarone type resins,including coumarone-indene resins and mixtures of coumarone resins,naphthenic oils, phenol resins, and rosins. Other suitable resinsinclude phenol-terpene resins such as phenol-acetylene resins,phenol-formaldehyde resins, alkyl phenol-formaldehyde resins,terpene-phenol resins, polyterpene resins, and xylene-formaldehyderesins.

Terpene-phenol resins may be used. Terpene-phenol resins may be derivedby copolymerization of phenolic monomers with terpenes such aslimonenes, pinenes and delta-3-carene. In one embodiment, the resin canbe an alpha pinene resin characterized by a softening point Tg between60° C. and 130° C.

In one embodiment, the resin is a resin derived from rosin andderivatives. Representative thereof are, for example, gum rosin, woodrosin and tall oil rosin. Gum rosin, wood rosin and tall oil rosin havesimilar compositions, although the amount of components of the rosinsmay vary. Such resins may be dimerized, polymerized ordisproportionated. Such resins may be in the form of esters of rosinacids and polyols such as pentaerythritol or glycol.

In one embodiment, said resin may be partially or fully hydrogenated.

In one embodiment, the rubber composition comprises from about 10 toabout 80 phr of at least one resin and, more preferably, from about 10to about 80 phr of a bio-derived resin, although embodiments arecontemplated in which another resin of a different type can be added tothe composition as well. In one embodiment, the rubber compositioncomprises no less than 15 phr of resin and, more preferably, no lessthan about 20 phr of resin. In one embodiment, the rubber compositioncomprises no less than 20 phr of resin and no more than 60 phr of resin.

The contemplated embodiment comprises between about 10% and 15% weightpercent of a bio-resin material in the composition. In one embodiment,the resin material makes up from about 12% weight percent and 15% weightpercent of the composition.

Filler

The disclosed rubber composition comprises 80-150 phr of silica filler.In one embodiment, the composition comprises at least 90 phr of silica.In one embodiment, the composition comprises no less than 100 phr ofsilica.

In one embodiment, the precipitated silica is comprised of:

-   (A) a precipitated silica derived from inorganic sand (silicon    dioxide based sand), or-   (B) a precipitated silica derived from rice husks (silicon dioxide    containing rice husks).

In one embodiment the precipitated silica is derived from naturallyoccurring inorganic sand (e.g. SiO₂, silicon dioxide, which may containa trace mineral content). The inorganic sand is typically treated with astrong base such as, for example, sodium hydroxide, to form an aqueoussilicate solution (e.g. sodium silicate). A synthetic precipitatedsilica is formed therefrom by controlled treatment of the silicate withan acid (e.g. a mineral acid and/or acidifying gas such as, for example,carbon dioxide). Sometimes an electrolyte (e.g. sodium sulfate) may bepresent to promote formation of precipitated silica particles. Therecovered precipitated silica is an amorphous precipitated silica.

In a preferred embodiment, the precipitated silica is a rice huskderived precipitated silica. Such precipitated silica is from derivedrice plant husks (e.g. burnt ashes from rice husks) which contain SiO₂,silicon dioxide, and which may contain trace minerals from the soil inwhich the rice has been planted). In a similar methodology, the ricehusks (e.g. rice husk ash) is typically treated with a strong base suchas, for example, sodium hydroxide, to form an aqueous silicate solution(e.g. sodium silicate) following which a synthetic precipitated silicais formed therefrom by controlled treatment of the silicate with an acid(e.g. a mineral acid and/or acidifying gas such as, for example, carbondioxide) in which an electrolyte (e.g. sodium sulfate) may be present topromote formation of precipitated silica particles derived from ricehusks. The recovered precipitated silica is an amorphous precipitatedsilica. For Example, see U.S. Pat. Application Serial No. 2003/0096900.In a preferred embodiment, the rubber composition comprises between 30and 40 weight percent of rice husk ash silica and, more preferably,between 34 and 37 weight percent of rice husk ash silica.

The precipitated silica, whether derived from the aforesaid silicondioxide or rice husks, may, for example, have a BET surface area, asmeasured using nitrogen gas, in the range of, for example, about 40 toabout 600, and more usually in a range of about 50 to about 300 squaremeters per gram. The BET method of measuring surface area might bedescribed, for example, in the Journal of the American Chemical Society,Volume 60, as well as ASTM D3037.

Such precipitated silicas may, for example, also have a dibutylphthalate (DBP) absorption value, for example, in a range of about 100to about 400, and more usually about 150 to about 300 cc/100 g.

Other embodiments are contemplated in which the silica is used incombination with another filler, such as carbon black.

In one embodiment, the rubber composition optionally comprises, based on100 parts by weight (phr) of elastomer, from about 0 to about 50 phr ofcarbon black. In one embodiment, the rubber composition comprises nomore than 10 phr of carbon black. In another embodiment, the rubbercomposition comprises no less than 0.1 phr of carbon black and, incertain embodiments, no less than 1 phr of carbon black. In oneembodiment, the rubber composition comprises from about 1 to about 10phr of carbon black. In a preferred embodiment, the carbon black is abio-based carbon black.

The ASTM-D6866 method to derive “bio-based” content is built on the sameconcepts as radiocarbon dating, but without use of the age equations.The method relies on determining a ratio of the amount of radiocarbon(¹⁴C) in an unknown sample to that of a modern reference standard. Theratio is reported as a percentage with the units “pMC” (percent moderncarbon). If the material being analyzed is a mixture of present-dayradiocarbon and fossil carbon (fossil carbon being derived frompetroleum, coal or a natural gas source), then the obtained pMC valuecorrelates directly to the amount of biomass material present in thesample.

The modern reference standard used in radiocarbon dating is a NationalInstitute of Standards and Technology USA (NIST-USA) standard with aknown radiocarbon content equivalent approximately to the year AD 1950,before excess radiocarbon was introduced into the atmosphere. AD 1950represents zero (0) years old and 100 pMC. Present day (fresh) biomassmaterials, and materials derived therefrom, give a radiocarbon signaturenear 107.5.

The radiocarbon dating isotope (¹⁴C) has a nuclear half-life of 5730years. Fossil carbon, depending upon its source, has very close to zero¹⁴C content. By presuming that 107.5 pMC represents present day biomassmaterials and 0 pMC represents petroleum (fossil carbon) derivatives,the measured pMC value for a material will reflect the proportions ofthe two component types. Thus, a material derived 100% from present dayvegetable oil would give a radiocarbon signature near 107.5 pMC. If thatmaterial was diluted with 50% petroleum derivatives, it would give aradiocarbon signature near 54 pMC.

A biomass content result is derived by assigning 100% equal to 107.5 pMCand 0% equal to 0 pMC. In this regard, a sample measuring 99 pMC willgive an equivalent bio-based content result of 93%. This value isreferred to as the “mean biobased result” and assumes all the componentswithin the analyzed material were either present day living or fossil inorigin.

The results provided by the ASTM D6866 method are the mean biobasedresult and encompass an absolute range of 6% (±3% on either side of themean bio-based result) to account for variations in end-componentradiocarbon signatures. It is presumed that all materials are presentday or fossil in origin. The result is the amount of bio-based component“present” in the material— not the amount of bio-based material “used”in the manufacturing process.

In one embodiment, a tire component is formed from a rubber compositioncomprising a carbon black filler having a greater than one percent (1%)modern carbon content as defined by ASTM D6866. The carbon black isproduced from a bio-based feedstock prior to its addition to the rubbercomposition. In one embodiment, the carbon black is at least partiallyderived from a bio-based feedstock and, in a preferred embodiment, iscompletely devoid of fossil carbon.

In one embodiment, the bio-based feedstock, from which the carbon blackis derived, comprises at least one triglyceride vegetable oil, such as,for example, soybean oil, sunflower oil, canola oil, rapeseed oil, orcombinations thereof. In one embodiment, the bio-based feedstock, fromwhich the carbon black is derived, comprises at least one plant biomass,animal biomass and municipal waste biomass, or combinations thereof.

In one embodiment, the carbon black has at least 1% modern carboncontent. In one embodiment, the carbon black has at least about 10% and,more preferably, at least about 25% and, most preferably, at least about50% modern carbon content. In one embodiment, the carbon black has abiomass content result of at least about 1 pMC and, more preferably, atleast about 54 pMC. In one embodiment, the carbon black may have abiomass content result of at least about 80 pMC.

Other embodiments are contemplated that employ a carbon-dioxidegenerated carbon reinforcing filler. Suitable carbon dioxide-generatedcarbon reinforcement may be produced using methods as described in US8,679,444; US 10,500,582; and U.S. Ser. No. 17/109,262—the contents ofwhich are each incorporated in their entirety herein, both of which arefully incorporated herein by reference.

Various combinations of carbon blacks (of differing particle sizesand/or other properties, including conventional, petroleum-carbon black)can also be employed in the disclosed rubber composition. Representativeexamples of rubber reinforcing carbon blacks are, for example, and notintended to be limiting, referenced in The Vanderbilt Rubber Handbook,13^(th) edition, 1990, on Pages 417 and 418 with their ASTMdesignations. Such rubber reinforcing carbon blacks may have iodineabsorptions ranging from, for example, 60 to 240 g/kg and DBP valuesranging from 34 to 150 cc/100 g.

Coupling Agent

Representative of silica coupler for said precipitated silica are:

-   (A) bis(3-trialkoxysilylalkyl) polysulfide containing an average in    range of from about 2 to about 4, alternatively from about 2 to    about 2.6 or from about 3.2 to about 3.8, sulfur atoms in its    connecting bridge, or-   (B) an alkoxyorganomercaptosilane, or-   (C) their combination.

Representative of such bis(3-trialkoxysilylalkyl) polysulfide iscomprised of bis(3-triethoxysilylpropyl) polysulfide.

The silica, discussed supra, is desirably added to the rubbercomposition in combination with the bis(3-triethoxysilylpropyl)polysulfide for reaction thereof in situ within the rubber composition.

In one embodiment, the composition comprises between about 1 phr andabout 20 phr of coupling agent and, more preferably, between from about8 phr and about 12 phr of coupling agent.

Processing Aid-Fatty Acid Derivatives

Another aspect of the present disclosure is the addition of abio-derived processing aid for the rubber composition. In a preferredembodiment, the processing aid can be a blend of bio-based fatty acidderivatives and/or bio-based fatty acid derivative(s). The processingaid can have a softening point (Tg) in the range of from about 105° C.to about 120° C. Generally, from about 0.5 to about 5 phr and, morepreferably, from about 1 to about 3 phr of processing aid may becomprised in the composition. In a contemplated embodiment, theprocessing aid be obtained as ZB 49 from Struktol® or others. In someembodiments, the processing aid can be used to promote coupling betweena coupling agent, silica filler and/or moieties on the polymer to thenetwork between the polymers.

It is readily understood by those having skill in the art that therubber composition would be compounded by methods generally known in therubber compounding art, such as mixing the various sulfur-vulcanizableconstituent rubbers with various commonly used additive materials suchas, for example, sulfur donors, curing aids, such as activators,accelerators and retarders and processing additives, fillers, pigments,fatty acid, zinc oxide, waxes, antioxidants and antiozonants andpeptizing agents. As known to those skilled in the art, depending on theintended use of the sulfur vulcanizable and sulfur-vulcanized material(rubbers), the additives mentioned above are selected and commonly usedin conventional amounts.

Representative examples of sulfur donors include elemental sulfur (freesulfur), an amine disulfide, polymeric polysulfide and sulfur olefinadducts. Preferably, the sulfur-vulcanizing agent is elemental sulfur.The sulfur-vulcanizing agent may be used in an amount ranging from 0.5to 8 phr, with a range of from 1 to 6 phr being preferred. Typicalamounts of antioxidants comprise about 0.5 to about 5 phr.Representative antioxidants may be, for example, polymerized trimethyldihydroquinoline, mixture of aryl-p-phenylene diamines, and others, suchas, for example, those disclosed in The Vanderbilt Rubber Handbook(1978), pages 344 through 346. In the preferred embodiment, theantioxidant is a lignin-based antioxidant. Typical amounts ofantiozonants comprise about 1 to 5 phr. A non-limiting representativeantiozonant can be, for example, N-(1,3 dimethylbutyl)-n′-phenyl-p-phenylenediamine. Typical amounts of fatty acids, ifused, which can include stearic acid as an example, can comprise about0.5 to about 5 phr. Typical amounts of zinc oxide comprise about 1 toabout 5 phr. In a preferred embodiment, the zinc oxide is derived fromrecycled content. Typical amounts of waxes comprise about 1 to about 5phr. Often microcrystalline waxes are used, but refined paraffin waxesor combinations of both can be used. Typical amounts of peptizerscomprise about 0.1 to about 1 phr. Typical peptizers may be, forexample, pentachlorothiophenol and dibenzamidodiphenyl disulfide.

Accelerators are used to control the time and/or temperature requiredfor vulcanization and to improve the properties of the vulcanizate. Inone embodiment, a single accelerator system may be used, i.e., primaryaccelerator. The primary accelerator(s) may be used in total amountsranging from about 0.2 to about 3, preferably about 2 to about 2.5 phr.In another embodiment, combinations of a primary and a secondaryaccelerator might be used with the secondary accelerator being used intotal amounts ranging from about 0.2 to about 3, preferably about 2 toabout 2.5 phr., in order to activate and to improve the properties ofthe vulcanizate. Combinations of these accelerators might be expected toproduce a synergistic effect on the final properties and are somewhatbetter than those produced by use of either accelerator alone. Inaddition, delayed action accelerators may be used which are not affectedby normal processing temperatures but produce a satisfactory cure atordinary vulcanization temperatures. Vulcanization retarders might alsobe used. A nonlimiting example of a retarder can beN-cyclohexylthiophthalimide (CTP). Suitable types of accelerators thatmay be used in the present invention are amines, disulfides, guanidines,thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates andxanthates. Preferably, the primary accelerator is a sulfenamide, suchas, for example, N-cyclohexyl-2-benzothiazolesulfenamide (CBS). If asecond accelerator is used, the secondary accelerator is preferably aguanidine (such as diphenyl guanidine (DPG)), dithiocarbamate (such aszinc dimethyl di-thiocarbamate or zinc dibenzyl di-thiocarbamate) orthiuram compound.

The mixing of the rubber composition can be accomplished by methodsknown to those having skill in the rubber mixing art. For example, theingredients are typically mixed in at least two stages, namely, at leastone non-productive stage followed by a productive mix stage. The finalcuratives including sulfur-vulcanizing agents are typically mixed in thefinal stage which is conventionally called the “productive” mix stage inwhich the mixing typically occurs at a temperature, or ultimatetemperature, lower than the mix temperature(s) than the precedingnon-productive mix stage(s). The terms “non-productive” and “productive”mix stages are well known to those having skill in the rubber mixingart. The rubber composition may be subjected to a thermomechanicalmixing step. The thermomechanical mixing step generally comprises amechanical working in a mixer or extruder for a period of time suitablein order to produce a rubber temperature between 140° C. and 190° C. Theappropriate duration of the thermomechanical working varies as afunction of the operating conditions, and the volume and nature of thecomponents. For example, the thermomechanical working may be from 1 to20 minutes.

Vulcanization of a pneumatic tire of the present invention is generallycarried out at conventional temperatures ranging from about 100° C. to200° C. Preferably, the vulcanization is conducted at temperaturesranging from about 110° C. to 180° C. Any of the usual vulcanizationprocesses may be used such as heating in a press or mold, heating withsuperheated steam or hot air. Such tires can be built, shaped, moldedand cured by various methods which are known and will be readilyapparent to those having skill in such art.

The disclosure contemplates a tire component formed from such method.Similarly, the tire component may be incorporated in a tire. The tirecomponent can be ground contacting or non-ground contacting. The tirecan be pneumatic or non-pneumatic. In one embodiment, the tire componentcan be a tread.

The tire of the present disclosure may be a race tire, passenger tire,aircraft tire, agricultural, earthmover, off-the-road, truck (commercialor passenger) tire, and the like. Preferably, the tire is a passenger ortruck tire. The tire may also be a radial or bias, with a radial beingpreferred.

The rubber composition itself, depending largely upon the selection andlevels of renewable materials, may also be useful as a tire sidewall orother tire components or in rubber tracks, conveyor belts or otherindustrial product applications, such as windshield wiper blades, brakediaphragms, washers, seals, gaskets, hoses, conveyor belts, powertransmission belts, shoe soles, shoe foxing and floor mats for buildingsor automotive applications.

The following examples are presented for the purposes of illustratingand not limiting the present invention. All parts are parts by weightunless specifically identified otherwise.

EXAMPLES

In these examples, the effects of the disclosed combinations ofrenewable content on the performance of a rubber compound areillustrated. Rubber compositions were mixed in a multi-step mixingprocedure following the recipes in Tables 1-6.

Control rubber compound Samples A, D, F, K, N and Q were formed of equalamounts of like ingredients. These Control Samples were formed using ablend of polybutadiene BR, emulsion polymerized styrene butadienecopolymer ESBR and solution polymerized styrene butadiene polymer ESBRwith additive materials including oil (soybean), a carbon black filler,a bio-based silane coupling agent, waxes, antiozonant, a lignin-basedantioxidant, a blend of bio-based fatty acid derivatives, and a recycledzinc oxide. The Controls were also formed using alpha methyl styreneresin, which is derived from petroleum. Standard curing techniques werealso used.

Example 1

Experimental Samples B and C are shown in Table 1. In Samples B and C,the petroleum resin is replaced with a bio-derived resin—moreparticularly, alpha pinene resin. Sample C also contains an eightpercent (8%) increase in sulfur and an accelerator over Control A, withall other ingredients and amounts being the same.

The rubber compounds were then cured and tested for various propertiesincluding, inter alia, wear, wet traction, and rolling resistance, etc.

The basic formulations are shown in the following Table 1, which ispresented in parts per 100 parts by weight of elastomer (phr). Table 1also compares the cured properties of Control Sample A and ExperimentalSamples B and C.

TABLE 1 Samples Control Experimental A B C BR¹ 44 44 44 ESBR 31 31 31SSBR² 30 30 30 Resin A³ 20 0 0 Resin B⁴ 0 20 20 Silica 95 95 95 Sulfur1.35 1.35 +8% Accelerator⁵ 2 2 +8% Viscosity, RPA at 100° C. G′, 15%(MPa) 0.228 0.223 0.228 Cure State Delta Torque (dNm) 19.3 18.3 22.7 T25(min) 7.3 6.3 6.2 T90 (min) 13.5 12.9 12.3 Stiffness RPA G′, 1% (MPa)4.134 4.009 4.046 RPA G′ 50% (MPa) 0.874 0.760 0.807 ARES at 30° C., G′(Pa) 6.34E±06 5.17E±06 4.72E±06 Wet Indicator Rebound at 0° C. (%) 21.621.4 21.1 ARES TD at 0° C. 0.402 0.417 0.459 Wear Indicators DINAbrasion (relative volume loss) 63 72 71 Grosch Abrasion High Severity607 566 565 (mg/km) Snow Indicator ARES G′ at -20° (Pa) 1.85E±071.55E±07 1.41 E±07 RR Indicator Rebound at 60° C. (%) 42.1 41.8 42.1ARES TD at 30° C. 0.310 0.320 0.339 ¹Polybutadiene, Nd catalyzed²Solution polymerized styrene butadiene rubber, 33% Styrene, 20 phr oilextended ³Alphamethyl styrene resin ⁴Bio-based terpene resin obtained asSYLVATRAXX 8115 from Kraton Chemical ⁵CBS

Table 1 displays a slight directional shift to lower stiffness betweenExperimental Sample B and Control A when the petroleum-derived resin isreplaced with a bio-derived resin. An increase in sulfur and anaccelerator between Experimental Sample C and Experimental Sample B—bothformed using the bio-derived resin—was made to adjust for the change.This improved the delta torque value of Sample C, which is a bettermatch to Control A.

Altogether, similar performance indicators were observed between theExperimental Samples B and C and Control A. It is concluded thatcompound performance is not impacted with a sustainably sourced resin inused place of a petroleum-based resin.

Example 2

Experimental Sample E is shown in Table 2. In Sample E, the conventionalpetroleum-derived carbon black is replaced with a bio-derived carbonblack. Sample E contains a greater amount of carbon black over ControlD, with all other amounts being the same.

The rubber compounds were then cured and tested for various propertiesincluding, inter alia, wear, wet traction, and rolling resistance, etc.

The basic formulations are shown in the following Table 2, which ispresented in parts per 100 parts by weight of elastomer (phr). Table 2also compares the cured properties of Control Sample D and ExperimentalSample E.

TABLE 2 Samples Control D* Experimental E Carbon Black (petroleum based)2 0 Carbon Black (bio-based)¹ 0 8 Viscosity, RPA at 100° C. 0.228 0.261G′, 15% (MPa) 0.228 0.261 Stiffness RPA G′, 1% (MPa) 4.134 4.497 RPA G′50% (MPa) 0.874 0.862 ARES at 30° C., G′ (Pa) 6.34E±06 2.00E+06 WetIndicator Rebound at 0° C. (%) 21.6 21.4 ARES TD at 0° C. 0.402 0.443Wear Indicators DIN Abrasion (relative volume loss) 63 70 GroschAbrasion High Severity (mg/km) 607 698 Snow Indicator ARES G′ at -20°(Pa) 1.85E±07 1.84E±07 RR Indicator Rebound at 60° C. (%) 42.1 42.5 ARESTD at 30° C. 0.310 0.335 *Same formula as Control Sample A, above¹Carbon black derived from CO₂ feedstock

Table 2 displays an increase in low strain stiffness betweenExperimental Sample E and Control D when the petroleum-derived carbonblack is replaced with a bio-derived carbon black.

Altogether, the bio-derived carbon black was shown to have no noticeableimpact on compound properties. It is concluded that the bio-derivedcarbon black can be used as a colorant without significantly impactingcompound performance.

Example 3

Experimental Samples G-J are shown in Table 3. In Samples G-J, the ESBRis replaced with natural rubber along with a reduction in SSBR. Sample Guses the conventional petroleum-derived resin with the modified rubberblend. Samples H-J replace the petroleum-derived resin with thebio-derived resin material. Samples I and J use an increased amount ofthe bio-derived resin material over Sample H. Sample J also increasesthe amount of silica filler over samples F-I. Minor cure adjustmentswere made between Samples H, I, and J, with all other ingredient amountsremaining the same.

The rubber compounds were then cured and tested for various propertiesincluding, inter alia, wear, wet traction, and rolling resistance, etc.

The basic formulations are shown in the following Table 3, which ispresented in parts per 100 parts by weight of elastomer (phr). Table 3also compares the cured properties of Control Sample F and ExperimentalSamples G-J.

TABLE 3 Samples Control Experimental F* G H I J BR¹ 44 44 44 44 44 ESBR31 0 0 0 0 SSBR² 30 24 24 24 24 Natural Rubber 0 36 36 36 36 Resin A³ 2020 0 0 0 Resin B⁴ 0 0 20 40 40 Silica 95 95 95 95 105 Viscosity RPA at100° C. G′, 15% (MPa) 0.181 0.215 0.183 0.129 0.149 Stiffness RPA G′, 1%(MPa) 3.805 4.282 3.733 2.116 2.780 RPA G′ 50% (MPa) 0.816 0.745 0.6480.447 0.457 ARES at 30° C., G′ (Pa) 4.92E±06 5.31E±06 5.76E±06 3.73E±064.69E±06 Wet Indicator Rebound at 0° C. (%) 21.2 23.8 24.0 16.7 16.0ARES TD at 0° C. 0.439 0.358 0.350 0.437 0.446 Wear Indicators DINAbrasion (relative volume loss) 66 50 39 81 76 Grosch Abrasion HighSeverity (mg/km) 462 419 338 298 271 Snow Indicator ARES G′ at -20° (Pa)1.54E±07 1.39E±07 1.46E±07 1.30E±07 1.58E±07 RR Indicator Rebound at 60°C. (%) 43.0 45.5 47.0 44.6 41.7 ARES TD at 30° C. 0.327 0.279 0.2810.320 0.336 *Same formula as Control Samples A and D, above¹Polybutadiene, Nd catalyzed ²Solution polymerized styrene butadienerubber, 33% Styrene, 20 phr oil extended ³Alphamethyl styrene resin⁴Bio-based terpene resin obtained as SYLVATRAXX 8115 from KratonChemical

In Example 3, the rubber polymer blend was adjusted to shift to a lowerpolymer Tg. The Experimental Samples G-J were tested to evaluate theimpact of the bio-derived resin and/or silica at increasing levels onpredicted performance.

By switching to natural rubber, Sample H demonstrated an increase in lowstrain stiffness. The shift to the lower polymer Tg resulted in anegative impact to wet indicators, but showed improved wear, snow androlling resistance indicators.

By doubling the amount of bio-derived resin, Sample I demonstrated asignificant improvement in wet indicators, but at the expense of rollingresistance. The increase in plasticizer level was directionallybeneficial for the snow indicator. Overall, the compound stiffness wasreduced.

By adding more silica in combination with the other changes, Sample Jdemonstrated that the stiffness was recovered. The snow indicator wasalso shown to be equivalent to the Control F.

It is concluded that performance characteristics can be controllablyimpacted, and the percent of renewable/sustainable content can beadjusted, by increasing the amount of bio-derived resin material andsilica in a tire. Such polymer composition can be incorporated into atire tread.

Example 4

Experimental Sample L, shown in Table 4, modifies sample J (which usedan increased amount of bio-derived resin material), supra, by furtherreplacing the petroleum-derived carbon black with equal parts ofbio-derived carbon black. In Sample M, the non-functionalized SSBR ofControl K and Sample L is replaced with a functionalized SSBR. Soybeanoil levels were also adjusted accordingly to maintain the plasticizerlevel of the oil-extended SSBR of Samples K and L.

Minor cure adjustments were made between Samples H, I, and J, with allother ingredient amounts remaining the same. All other ingredients andamounts of Sample L are the same as Sample J, which comprises thebio-derived resin over the petroleum resin of Control K and a greateramount of silica filler. Minor cure adjustments were also made to SampleK.

The rubber compounds were then cured and tested for various propertiesincluding, inter alia, wear, wet traction, and rolling resistance, etc.

The basic formulations are shown in the following Table 4, which ispresented in parts per 100 parts by weight of elastomer (phr). Table 4also compares the cured properties of Control Sample K and ExperimentalSamples L and M.

TABLE 4 Samples Control Experimental K* L** M BR¹ 44 44 45.4 ESBR 31 0 0Natural Rubber 0 36 36 SSBR A² 30 24 0 SSBR B³ 0 0 18.6 Resin A⁴ 20 0 0Resin B⁵ 0 40 40 Silica⁶ 95 105 105 Carbon Black (petroleum based) 2 0 0Carbon Black (bio-based)⁷ 0 2 2 Vascosity, RPA at 100° C. G′, 15% (MPa)0.192 0.157 0.179 Stiffness RPA G′, 1% (MPa) 3.828 2.755 2.798 RPA G′50% (MPa) 0.782 0.495 0.520 ARES at 30° C., G′ (Pa) 4.66E±06 3.71E±064.57E±06 Wet Indicators Rebound at 0° C. (%) 21.2 14.1 15.7 ARES TD at0° C. 0.459 0.507 0.422 Wear Indicator DIN Abrasion (relative volumeloss) 60 84 73 Grosch Abrasion High Severity (mg/km) 396 337 288 SnowIndicator ARES G′ at -20° (Pa) 1.46E±07 1.38E±07 1.51E+07 RR IndicatorRebound at 60° C. (%) 42.2 40.4 41.6 ARES TD at 30° C. 0.340 0.363 0.304*Same formulation as Control Samples A, D and F, above **Sameformulation as Sample J above, except with addition of bio-based carbonblack ¹Solution polymerized styrene butadiene rubber, 33% Styrene, 20phr oil extended ²SSBR, 33% styrene, 20 phr oil extended ³SSBR, 21%styrene, functionalized, Sn ⁴Alphamethyl styrene resin ⁵Bio-basedterpene resin obtained as SYLVATRAXX 8115 from Kraton Chemical ⁶Ricehusk ash silica ⁷Carbon black derived from CO₂ feedstock

Sample M showed no impact on compound properties when petroleum-derivedcarbon black is replaced with bio-derived carbon black. Here thecombination of bio-derived carbon black and bio-derived resin materialis tested with the high silica content and a functionalized SBR. The useof the functionalized SBR in place of non-functionalized SBRdemonstrated an improved rolling resistance. Minimal impact was observedto other performance indicators. Thus, it is concluded that afunctionalized polymer can be used in a tire tread rubber compositionwith multiple other bio-derived materials.

Example 5

Experimental Sample O is the same formula as Sample M, supra. Sample Padjusts the polymer ratio of Sample O, with all other ingredients andamounts being the same. This change led to an increase in the percentamount of renewable material (content) in the composition.

The rubber compounds were then cured and tested for various propertiesincluding, inter alia, wear, wet traction, and rolling resistance, etc.

The basic formulations are shown in the following Table 5, which ispresented in parts per 100 parts by weight of elastomer (phr). Table 5also compares the cured properties of Control Sample N and ExperimentalSamples O and P.

TABLE 5 Samples Control Experimental N* O^(∗∗) P BR 44 45.4 45.4 ESBR 310 0 Natural Rubber 0 36 45 SSBR A¹ 30 0 0 SSBR B² 0 18.6 9.6 Resin A³ 200 0 Resin B⁴ 0 40 40 Silica⁵ 95 105 105 Carbon Black (petroleum based) 20 0 Carbon Black (bio-based)⁶ 0 2 2 Percent (%) recycled/renewable 47 7275 Viscosity, RPA at 100° C. G′, 15% (MPa) 0.213 0.168 0.170 StiffnessRPA G′, 1% (MPa) 4.320 2.864 3.242 RPA G′ 50% (MPa) 0.900 0.552 0.548ARES at 30° C., G′ (Pa) 4.49E±06 3.34E±06 3.60E±06 Wet Indicator Reboundat 0° C. (%) 20.9 14.5 15.5 ARES TD at 0° C. 0.451 0.496 0.456 WearIndicators DIN Abrasion (relative volume loss) 53 not tested 50 GroschAbrasion High Severity (mg/km) 626 485 481 Snow Indicator ARES G′ at-20° (Pa) 1.39E±07 1.16E±07 1.14E±07 RR Indicator Rebound at 60° C. (%)42.0 42.4 40.7 ARES TD at 30° C. 0.331 0.346 0.340 *Same formula asControl Samples A, D, F and K, above **Same formula as Sample M, above¹SSBR, 33% styrene, 20 phr oil extended ²SSBR, 21% styrene,functionalized, Sn ³Alphamethyl styrene resin ⁴Bio-based terpene resinobtained as SYLVATRAXX 8115 from Kraton Chemical ⁵Rice husk ash silica⁶Carbon black derived from CO₂ feedstock

Prior to this example, Sample M demonstrated the most favorableperformance results. In Example 5, the ratio blend of the three polymerswere adjusted and compared to Sample M. This adjustment resulted in apolymer Tg shift (FOX calculation) from -80.0° C. to -82.6° C.

The increase in the natural rubber content of Experimental Sample Pdemonstrated an increase in compound stiffness. Sample P improved wet,wear and snow indicators compared to Control N while also containing asubstantial percent increase in renewable material content. The rollingresistance indicators were also equivalent to or improved on Control Nand Sample O.

Table 6

Experimental Sample R is the same formula as Sample P, supra. In SampleS, the ESBR was replaced with a greater amount of natural rubber. Allother ingredients and amounts remained the same. This change led to afurther increase in the percent amount of renewable material (content)in the composition.

The rubber compounds were then cured and tested for various propertiesincluding, inter alia, wear, wet traction, and rolling resistance, etc.

The basic formulations are shown in the following Table 6, which ispresented in parts per 100 parts by weight of elastomer (phr). Table 6also compares the cured properties of Control Sample Q and ExperimentalSamples R and S.

TABLE 6 Samples Control Experimental Q* R^(∗∗) S BR 44.0 45.4 17.0 ESBR31 0 0 Natural Rubber 0 45 83 SSBR A¹ 30 0 0 SSBR B² 0 9.6 0 Resin A³ 200 0 Resin B⁴ 0 40 40 Silica⁵ 95 105 105 Carbon Black (petroleum based) 20 0 Carbon Black (bio-based)⁶ 0 2 2 Percent (%) recycled/renewable 45 7588 Viscosity, RPA at 100° C. G′, 15% (MPa) 0.234 0.169 0.152 StiffnessRPA G′, 1% (MPa) 4.605 3.441 3.285 RPA G′ 50% (MPa) 0.876 0.522 0.495ARES at 30° C., G′ (Pa) 5.87E±06 4.27E±06 3.65E±06 Wet Indicator Reboundat 0° C. (%) 21.5 17.0 14.5 ARES TD at 0° C. 0.397 0.419 0.469 SnowIndicator ARES G′ at -20° (Pa) 1.82E±07 1.40E±07 1.22E±07 RR IndicatorRebound at 60° C. (%) 43.3 42.8 43.3 ARES TD at 30° C. 0.306 0.318 0.354*Same formulas as Control Samples A, D, F, K, and N above **Same formulaas Sample P, above ¹SSBR, 33% styrene, 20 phr oil extended ²SSBR, 21%styrene, functionalized, Sn ³Alphamethyl styrene resin ⁴Bio-basedterpene resin obtained as SYLVATRAXX 8115 from Kraton Chemical ⁵Ricehusk ash silica ⁶Carbon black derived from CO₂ feedstock

To further test an increase to the percent amount of renewable contentin a tread, the SBR was removed and replaced with additional naturalrubber. Also, in this example the natural rubber made up the majoritycontent, at a substantial increase, of rubber polymer in the blend. Thisresulted in a polymer Tg (FOX calculation) shift from -82.6° C. to-72.3° C.

The polymer adjustments resulted in a slight decrease in compoundstiffness.

The increase in natural rubber level increased the percent of renewablecontent in the rubber composition from 47% weight (Control Q) to 88%weight (Experimental Sample S). Sample S showed improved wet and snowindicators over Control Q, and it also indicated an equivalent rollingresistance.

Experimental Sample U is the same formula as Sample P and ExperimentalSample V is the same as Experimental Sample S, supra. ExperimentalSamples W used greater parts of bio-derived carbon black when comparedto Sample V. Experimental sample X used mass-balanced polybutadiene inplace of conventional butadiene and rice husk ash silica in place ofconventional silica. This change led to a further increase in thepercent amount of renewable material (content) in the composition. Allother ingredients and amounts remained the same. Table 7 reports thecured properties of the resultant material.

The rubber compounds were then cured and tested for various propertiesincluding, inter alia, wear, wet traction, and rolling resistance, etc.

Table 7 compares the cured properties of Control Sample T andExperimental Samples U, V, W and X.

TABLE 7 Samples Control Experimental T* U^(∗∗) V^(∗∗∗) W X BR 44.0 45.417.0 17.0 0 Mass balanced BR 0 0 0 0 17.0 ESBR 31 0 0 0 0 Natural Rubber0 45 83 83 83 SSBR A¹ 30 0 0 0 0 SSBR B² 0 9.6 0 0 0 Resin A³ 20 0 0 0 0Resin B⁴ 0 40 40 40 40 Conventional silica 95 105 105 105 0 Rice huskash silica 0 0 0 0 105 Carbon Black 2 0 0 0 0 (conventional) CarbonBlack⁵ 0 2 2 10 10 Potential percent (%) recycled/renewable 45 75 88 8994 RPA Uncured G′(MPa) 0.218 0.151 0.135 0.142 0.142 RPA G′, 1% (MPa)4.440 3.238 3.029 3.280 3.280 RPA G′ 50% (MPa) 0.956 0.594 0.485 0.4730.473 Tan Delta 10% 0.200 0.222 0.231 0.235 0.235 Rebound Rebound at 0°C. (%) 20.92 17.00 13.77 13.50 13.50 Rebound at 23° C. (%) 31.77 30.7127.10 26.53 26.53 Rebound at 100° C. (%) 47.66 50.09 47.66 44.14 44.14MTE 300% Modulus (MPa) 6.92 6.84 6.31 5.91 5.91 Tensile Strength (MPa)17.79 15.31 12.19 11.66 11.66 Elongation (%) 661 625 548 566 566Abrasion Din Rel Vol Loss 68 65 141 159 159 ARES G′ -20° C. (Pa)1.52E±07 1.34E±07 1.36E±07 1.60E±07 1.60E±07 G′ 30° C. (Pa) 5.20E±064.28E±06 4.06E±06 4.92E±06 4.92E±06 Tan Delta 0° C. 0.385 0.041 0.4140.400 0.400 Tan Delta 30° C. 0.291 0.304 0.329 0.310 0.310 *Same formulaas Control Samples A, D, F, K, and N above **Same formula as Sample P,above ***Same formula as Sample S, above ¹SSBR, 33% styrene, 20 phr oilextended ²SSBR, 21% styrene, functionalized, Sn ³Alphamethyl styreneresin ⁴Bio-based terpene resin obtained as SYLVATRAXX 8115 from KratonChemical ⁵Carbon black derived from CO₂ feedstock

FIG. 1 maps out key performance indicators between the Control T andExperimental Samples U, V, W and X. As displayed in the FIGURE, many ofthe main properties of Sample U are equivalent to the Control T based onlab indicators. The wet and snow indicators for Samples V, W and X aresimilar. Both are equivalent and/or directionally better than Control T.

It is concluded that a tread tire rubber composition formed having amajority percent of renewable content from a combination of differentrenewable materials can meet or improve the performance of a tire formedfrom a conventional rubber composition.

Variations in the present invention are possible in light of thedescription of it provided herein. While certain representativeembodiments and details have been shown for the purpose of illustratingthe subject invention, it will be apparent to those skilled in this artthat various changes and modifications can be made therein withoutdeparting from the scope of the subject invention. It is, therefore, tobe understood that changes can be made in the particular embodimentsdescribed which will be within the full intended scope of the inventionas defined by the following appended claims.

What is claimed is:
 1. A tire component formed from a rubber compositioncomprising a majority weight percent of renewable materials, the rubbercomposition comprising, based on 100 parts per weight (phr) ofelastomer: a blend of at least two rubber elastomers selected from agroup consisting of: from about 15 phr to about 50 phr polybutadiene; upto about 20 phr of styrene-butadiene copolymer; up to about 90 phr ofnatural rubber; a bio-derived resin material; a vegetable triglycerideoil; and a bio-derived filler comprising silica and carbon black filler,wherein said carbon black filler is at least partially derived from abio-based feedstock prior to its addition to the rubber composition. 2.The tire component of claim 1, wherein the rubber composition comprisesgreater than about 75% of sustainable material.
 3. The tire component ofclaim 1, wherein the rubber composition comprises greater than about 85%of sustainable material.
 4. The tire component of claim 1, wherein therubber composition comprises greater than about 90% of sustainablematerial.
 5. The tire component of claim 1, wherein the resin is aterpene resin.
 6. The tire component of claim 1, wherein the resin is analpha pinene resin.
 7. The tire component of claim 1, wherein thecomposition excludes a petroleum-derived resin, oil, and fillermaterial.
 8. The rubber composition of claim 1, wherein thepolybutadiene is a mass-balanced polybutadiene.
 9. The rubbercomposition of claim 1, wherein the blend of rubber elastomers excludesemulsion polymerized styrene butadiene copolymer (ESBR).
 10. The rubbercomposition of claim 1, wherein the blend of rubber elastomers comprisesfrom about 5 to about 30 phr of solution polymerized styrene butadienecopolymer (SSBR).
 11. The rubber composition of claim 9, wherein theSSBR is oil extended.
 12. The rubber composition of claim 9, wherein theSSBR is functionalized.
 13. The rubber composition of claim 9, whereinthe SSBR is not functionalized.
 14. The rubber composition of claim 9,wherein the blend of rubber elastomers comprises from about 5 to about15 phr of functionalized SSBR.
 15. The rubber composition of claim 1,wherein the blend of rubber elastomers comprises from about 35 phr toabout 90 phr of natural rubber.
 16. The rubber composition of claim 14,wherein the blend of rubber elastomers further excludes ESBR.
 17. Therubber composition of claim 1 further comprising: from about 50 phr toabout 200 phr of silica; and from 1 to about 15 phr of carbon black. 18.The rubber composition of claim 1, wherein the silica is derived fromrice husk ash.
 19. The rubber composition of claim 1 further comprisingfrom about 10 phr to about 50 phr of resin.
 20. The tire component ofclaim 1, wherein, prior to its addition to the rubber composition, thecarbon black is produced from a feedstock that excludes fossil carbon.